Distorted SSB TX audio - Did you fix it?

[SP9TKW]

I decided to ignore buzzing sound and installed firmware 2.0x again. Modulation is still distorted.

As I am planning to do some SOTA over next few days I installed old LO band board I had with 3xBS170. Surprise surprise modulation is fine.

I changed PA MOSFET on Classic band board and tried again, Still the same problem - modulation is distorted. It looks like board is damaged, am I right or some settings need adjusting?

Could I install 3xBC170? would that help?

Thx for any help, I would like to avoid buying new Classic board.

73 Marek

[Rocky]

Hi Marek, you are certainly putting in the effort! Thanks for your progress reports.
Intriguing that the old LO board cured the distortion. Where can a new classic board be obtained from?

[SP9TKW]

The Classic board was purchesed from UpTech Store on Aliexpress, so recommended source.

73 Marek

[Karavan]

I have encountered a similar problem.
Correspondents complained about poor modulation.
I don't have any specialized equipment, so with the help of SDR RSP1 I saw that the frequency on the display of the transceiver does not correspond to reality.
In the paragraph "8.3 Ref freq" I selected the value "26997800".
The problem has been solved.
I also noticed a feature, if you do not reboot the transceiver for a long time, the modulation and power deteriorate greatly. This applies to the R2.00x firmware, this has not been noticed on the R2.00i firmware.

[Rocky]

Yes, calibrating the transmit frequency of the truSDR by adjusting the reference frequency, menu 8.3, to match what is being received by the listening station as per DL2MAN's "how to Calibrate Frequency" vid in the manual, seems to have resolved the issue for me also. The record function in KiwiSDR has been super helpful in sorting this issue.

[DH7CS]

Dear Marek,
have my TRX since 3-4 months but noth much time spend in usin it.
did yesterday a feq calibtation as i had the feeling i´m not on the correct frequency.

have now also this strange Signal, without pressing PTT.

excause me my low technical knowledge - did start my OM-carrier only Aug 2023 and need to lern much

another OM with more knowledge about electronics has the same problem but also no idea.

can you pls advise if this issue has been already solved?
if yes, can you pls share the solition?

many thanks & 73
Chris
DH7CS

[SP9TKW]

Hi Chris,

Sorry for a late reply but I wasn't on forum for awhile.

Not sure how to reply to your problem and what advise to give apart from creating new thread and describing in detail your problem.

As for my issue it is still there and actually gave up on it. Rig works OK in CW and Digi modes, its just SSB which is an issue.

One day in winter I might come back to it. Maybe I am repeating the same errors during reinstall of Bootloader and Firmware. I hope that in a few months once I forgot how to do it I will follow instructions better and will not repeat error (if any).

73 Marek

[hwoering]

In reading all your posts, what worked for me was adding a ferrite onto the antenna input and reducing the TX Drive (3.3) to 4 and then to 6. I am getting good signal and audio reports. I am also using a Baofeng external mic. It is plugged into the Mic/Key plug and I use the onboard PTT. Thanks to all here for your technical advise. Very pleased with the (tr)SDX.
Harold de N1FTP

(I did not reload the firmware)